CORRESPONDENCE AND RESPONSE; Determination of Total Nitrogen

Fertilizers

“…Much attention has recently been given to the use of selenium and its compounds (24,48,55,62,130,131,136,184,109,202,205,206,211,226,258), alone or in combination with other catalysts, which effect more rapid oxidation of the organic matter and shorten the digestion time but may cause some loss of nitrogen if the digestion is unduly prolonged (62,202). Better recovery of the nitrogen is said to be obtained with combinations of selenium and mercuric oxide (55, 202), and the selenates of copper, cadmium, and calcium, in the decreasing order, are reported to be more efficient than elemental selenium (62).…”

Selenium as Catalyst in Kjeldahl Digestions

“…is obtained when a combination of selenium and mercuric oxide is,used as catalyst; this is due to the THE catalytic effect of small amounts of selenium, selenium oxychloride, selinites, or selenates in the oxidative digestion of nitrogenous organic matter by the Kjeldahl method is well known (5,13,17,20,28,32). A combination of mercuric oxide and selenium acts much more effectively than either of them singly in accelerating the decomposition of proteins (1,4, #3, 25, S3, So).…”